Question

question 4 1 pts how do polar compounds, such as amino acids, enter a cell?
without assistance
by dissolving into the lipid bilayer
thru hydrolysis
transported across membrane by proteins

Explanation:

Polar compounds like amino acids can't pass the non - polar lipid bilayer easily. They need membrane proteins (like transporters) to cross. "Without assistance" is wrong as polar molecules can't freely cross. Dissolving in lipid bilayer is wrong (lipid bilayer is non - polar). Hydrolysis is a breakdown process, not transport. So the correct mechanism is transport via proteins.

Answer:

transported across membrane by proteins